Zoe and Barbara collected buttons. Zoe gave 30% of her buttons to Barbara and as a result, Barbara's buttons increased by 25%. If Zoe had 56 buttons left, find the number of buttons Barbara should give to Zoe in the end so that both had an equal number of buttons.

	Zoe	Barbara	Comparing the change in Barbara's buttons
Before	10x1 = 10 u		4x3 = 12u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		5x3 = 15 u

30% = ³⁰₁₀₀ = ³₁₀
25% = ²⁵₁₀₀ = ¹₄

The increase in the number of buttons that Barbara had is repeated.  Make the increase in the number of buttons that Barbara had the same. LCM of 3 and 1 = 3

7 u = 56

1 u = 56 ÷ 7 = 8

Number of buttons that Barbara had more than Zoe in the end
= 15 u - 7 u
= 8 u

Number of buttons that Barbara should give to Zoe so that both had an equal number of buttons in the end
= 8 u ÷ 2
= 4 u
= 4 x 8
= 32

Answer(s): 32